Soft Growth

Mar 10, 2011 • Andrew Walladge

If you have noticed trees or branches falling down with monotonous regularity lately, you are not the only one. If you are also wondering why, the perfectly logical explanation put simply is ‘soft growth’.

The above average summer rainfall makes grape growers groan and gardeners rejoice, however the down side for gardeners is that almost everything in the garden has produced very soft growth. The leaves are softer than usual, the small stems, branches and even the developing timber is much softer than usual. All this living tissue (cells) is pumped up to the max and as a consequence is heavier than usual. Add soft wet soil and wind to the mix and the result is almost inevitable. If trees don’t fall down completely, trunks can snap or limbs break.

Why then don’t all trees fall down? I’m glad you asked. If plants are weakened already by poor species selection ( the plant is not coping with the situation), over rich soils and over watering in the past or a combination of all of the above then the plant root system may well be restricted or simply ‘lazy’ to the point it can’t hang on.

Take a local mallee as an example; it would normally be quite happy on our local soils with no fertiliser or irrigation once it had got through a couple of summers. However that all changes if it was suddenly next to a new lawn or shade house. Plenty of water near the surface and higher than usual quantities of nutrient in the soil. The tree will then develop a root system to take advantage of the situation (as would any tree). A shallow root system and a lush thick canopy would develop. It would probably be fine for several years but add way above average summer rain when the canopy would normally thin out a little and you will have a tree that is highly vulnerable to wind damage.

Deciduous trees can still be at risk with this scenario, however they will tend not to produce such out of proportion soft growth because their growth is normally trying to be softer than the conditions will allow anyhow.

Young plants of almost any sort can be as risk because we are trying to encourage new growth with water and fertiliser and it is easy to go overboard in such a wet summer (for us in the Riverland and Mallee).

To remedy the situation, prune young plants now and let the soil dry a little more to encourage deeper roots. For older plants (including large mature trees) look around under the canopy and at least the trees height away for extra watering that may be contributing to the problem and then ‘stretch’ watering patterns to suit the tree(s) better. For suspect trees get another opinion and even restrict your activities under them while soft growth is present. This time could extend until well into spring this year.